Examining the relationships among health-related quality-of-life indicators in cancer patients participating in clinical trials: a pooled study of baseline EORTC QLQ-C30 data

Abstract

Aims: Cancer patients experience multiple and concurrent health-related problems and symptoms due to their illness and therapies. The first objective of this analysis was to identify how health-related quality-of-life (HRQoL) indicators cluster among cancer patients and how possible clusters change across patients with different sociodemographic and clinical characteristics. The second objective of this study was to identify which HRQoL indicators are linked to patients’ perception of overall quality of life. Methods: Retrospective pooling of 30 closed randomized European Organisation for Research and Treatment of Cancer (EORTC) clinical trials yielded baseline EORTC Quality of Life Core Questionnaire (QLQ-C30) HRQoL data for a total of 7417 patients. A cluster analysis was performed to determine how the 15 HRQoL indicators obtained with the QLQ-C30 cluster overall and by patient characteristics. Results: Three main clusters emerged from the overall dataset: a physical cluster, a psychological cluster and a gastrointestinal cluster. The same clusters were found in subgroups defined according to sociodemographic and clinical characteristics, while some differences emerged among cancer sites. The Global Health scale was found to be part of the physical cluster in the overall dataset. This result was consistent across different levels of disease severity, while divergent results were seen across some cancer sites. Conclusion: Our findings suggest that HRQoL indicators are interrelated. Understanding these relationships may aid clinicians in managing the symptom burden experienced by patients, as well as policy-makers, in defining psychosocial support plans.

Keywords::

• cancer
• clinical trials
• cluster analysis
• patient-reported outcomes
• quality of life

Acknowledgements

The authors thank the EORTC Headquarters, EORTC Clinical Groups and all the principal investigators: W Albrecht, J Becker, JSA Belderbos, J Bernier, F Cognetti, RE Coleman, T Conroy, R de Wit, A Eggermont, S Fossa, G Giaccone, JC Horiot, U Keilholz, F Keuppens, CH Koehne, JL Lefebvre, F Levi, GON Oosterhof, M Piccart, P Postmus, HJ Schmoll, ALJ Schutser-Uitterhoeve, EF Smit, TAW Splinter, M Taphoorn, P Therasse, MJ Van Den Bent, J Van Meerbeek, H Van Poppel and N Van Zandwijk. Thanks to Cecilia Liberatoscioli and Javier O Valenzuela for the clinical advice and to Sheila Scott-Sanderson for editing the manuscript. Lastly, a very special thank you to all the patients who participated in these trials.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.

Financial & competing interests disclosure

This study was funded by an unrestricted academic grant from the Pfizer Foundation, administered through the King Baudouin Foundation, for the EORTC PROBE group. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.